Recently, disk devices such as magnetic disk drives and optical disk drives have become widely used as external recording devices and image storage devices of computers.
As a disk device, for example, the magnetic disk drive generally comprises a magnetic disk arranged in a case, a spindle motor for supporting and rotating the magnetic disk, a carriage assembly for supporting a magnetic head, a voice coil motor (VCM) for driving the carriage assembly, a circuit board unit, and the like.
The carriage assembly includes a bearing unit and a plurality of arms, which are stacked on the bearing unit and extend from the bearing unit, and the magnetic head is attached to each of the arms via a suspension. The magnetic head, the suspension, and the arm configure a head suspension assembly.
There is provided a magnetic disk drive wherein damper members are bonded to the arms in order to inhibit the arms from vibrating due to an airflow produced in the magnetic disk drive by rotation of the magnetic disk. Further, there is provided a magnetic disk drive wherein arms have through holes between the upper and lower surfaces and a seal member is attached to the arms so as to reduce a disturbance of an airflow to the arms. The seal member is formed to have a U-shaped cross section or a rectangular cross section and attached to the arm from a side or from a head side. A projection is formed on an upstream side or a downstream side to diffuse the airflow up and down.
In the magnetic disk device, when the projection is provided on the upstream side or the downstream side of the arms and the airflow is diffused up and down, there is a possibility that the projection is vibrated up and down by the airflow and the vibration causes a head suspension assembly to vibrate. It is considered that the magnetic head is vibrated accordingly, so that a positioning accuracy is deteriorated.